Fisher automatic changeover regulators change from the supply cylinder (when gas is exhausted) to the reserve cylinder automatically. Type 749B is a large capacity changeover manifold for commercial and industrial applications. It consists of two 64 Series regulators and a Type 803 direct indicator. The assembly is used primarily in conjunction with either a Type HSRL or 64SR regulator.
Note: These units are intended for use with Second-Stage regulators and/or separate relief devices which provide overpressure protection required by NFPA 58. Capacity of all these changeover manifolds is dependent on the size of the Second-Stage regulator with which they are used. If the manifolds are used as a Final-Stage (pounds-to-pounds), a relief valve is required in the downstream system.
Specifications
- Capacity: 1,500,000 BTU/hr (11.3 SCMH)
- Inlet Connection: 1/2 in. FNPT
- Outlet Connection: 1/2 in. FNPT
- Maximum Inlet Pressure: 250 psig (17.2 bar)
- Maximum Emergency Outlet Pressure:
- For Type 64 Regulators Used: 220 psig (15.2 bar)
- For Type HSRL Final Stage Regulator: 3 psig (0,21 bar)
- Standard Outlet Setting:
- Supply: 15 psig (1 bar)
- Reserve: 5 psig (0,34 bar)
- Temperature Capabilities: -20° to 160°F (-29° to 71°C)
- UL Listed: Type 749B, Second-Stage Regulators are Listed Separately
